Microwave plasma treatment device for low-radioactivity hazardous waste

Abstract

The invention discloses a low-radioactivity hazardous waste microwave plasma treatment device, and belongs to the technical field of hazardous waste treatment. Comprising an electrothermal furnace, a microwave plasma waste gas treatment device, a deacidification device, a cooling device and an adsorption device which are sequentially connected through pipelines. The electrothermal furnace is used for heating the hazardous waste in an oxygen-free environment, so that organic pollutants are gasified and separated, and radionuclides are solidified in the slag. According to the microwave plasma waste gas treatment device, high-temperature plasma is generated through microwave excitation, and organic waste gas is thoroughly cracked. And the deacidification, cooling and adsorption device is used for carrying out multi-stage purification on the cracking gas. By means of the device, efficient volume reduction of radioactive waste, thorough harmlessness of organic pollutants and clean emission of tail gas are achieved, and the problems that a traditional disposal mode is large in size and high in cost, and secondary pollution risks exist are solved.

Description

Technical Field

[0001] This invention relates to the field of hazardous waste treatment technology, and more specifically, to a microwave plasma treatment device for low-radioactive hazardous waste. Background Technology

[0002] Low-level radioactive waste is a term used in the nuclear energy field, referring to radioactive waste with low levels of radioactivity and limited content of long-lived nuclides. According to Chinese national standards, it typically refers to solid waste with a specific activity within a certain range. It constitutes a large proportion of the total volume of nuclear waste, but its total radioactivity percentage is very low.

[0003] Traditionally, such waste has been primarily disposed of through integrated methods such as solidification, landfilling, and sealing. While these methods can isolate radioactive materials, they fail to effectively separate the mixed organic and inorganic pollutants from the radionuclides. This results in a massive volume of material requiring final disposal, high disposal costs, and significant landfill space requirements. Furthermore, the organic components are not completely decomposed, posing long-term environmental risks. Although incineration and melting methods have emerged to reduce volume, challenges remain in preventing secondary pollution, controlling radionuclide migration, and minimizing energy consumption.

[0004] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0005] In view of the problems in related technologies, the present invention proposes a microwave plasma treatment device for low-radioactive hazardous waste to overcome the above-mentioned technical problems existing in the existing related technologies.

[0006] Therefore, the specific technical solution adopted by the present invention is as follows: A microwave plasma treatment device for low-radioactive hazardous waste includes an electric furnace, a microwave plasma waste gas treatment device, a deacidification device, a cooling device, and an adsorption device connected in sequence by pipelines. The electric furnace is configured to create an oxygen-free environment by evacuating the furnace or introducing inert gas to replace the air inside the furnace, and to heat the low-radioactive hazardous waste in an oxygen-free environment, causing the organic pollutants and volatile inorganic substances in the waste to be vaporized and separated from radioactive nuclides and heavy metals, forming organic waste gas and solid slag; the electric furnace is also equipped with a slag collection bin for collecting solid slag containing radioactive nuclides and heavy metals, which facilitates subsequent safe disposal. The microwave plasma exhaust gas treatment device incorporates a microwave plasma torch generator. Through the interaction of high-frequency microwaves and the working gas, it induces ionization and collision cascade effects, forming plasma gas and generating electrodeless microwave discharge. This produces freely floating plasma particles, which, utilizing their high-temperature characteristics, decompose the organic components in the received organic waste gas into H2O, CO2, and NO. x Simple gases; The deacidification device, cooling device, and adsorption device are configured in sequence to deacidify, cool, and deeply purify the pyrolysis tail gas to achieve compliant gas emissions.

[0007] As a further aspect of the present invention, the furnace shell of the electric furnace is made of a high-temperature resistant and corrosion-resistant material. The temperature of the oxygen-free heating is controlled within a range that allows the target components in the hazardous waste to be effectively gasified while the solid slag is stably retained. This ensures that the target pollutants can be effectively gasified while maintaining a stable mineral structure in the residual slag, preventing the re-evaporation of radioactive nuclides.

[0008] As a further aspect of the present invention, the working gas of the microwave plasma torch generator is one or more of inert gas, ordinary air, and waste gas to be treated; the center temperature of the plasma particle can reach up to 3000K, and electrodeless microwave discharge can be started in the outflow opening area within about 1 microsecond after the magnetron is turned on.

[0009] As a further embodiment of the present invention, the deacidification device is a ceramic deacidification filter, the core component of which is a porous ceramic filter element with a microporous structure. The porosity of the ceramic filter element is greater than 80%, the micropore diameter ranges from 1 to 10 micrometers, and its surface is coated with an adsorbent or catalyst. This allows the filter element to not only capture particulate matter through physical interception, but also to simultaneously perform chemical adsorption or catalytic conversion of acidic gases, thereby achieving integrated dust removal and deacidification.

[0010] As a further embodiment of the present invention, the cooling device is a spray tower, which has an atomizing spray layer and a packing layer arranged from top to bottom inside; the atomizing spray layer is used to spray coolant onto the rising airflow, and the packing layer is used to increase the gas-liquid contact area, so as to achieve rapid cooling of high-temperature gas and washing off some particulate matter through evaporative cooling and sensible heat exchange.

[0011] As a further embodiment of the present invention, the adsorption device adopts a ceramic dust filter. The ceramic dust filter captures particles through a curved porous ceramic channel by means of interception, inertial action and diffusion effect. The filtration efficiency for particles with a diameter of 0.1μm is not less than 99.9%, ensuring the cleanliness of the outlet gas.

[0012] The present invention also provides a processing method based on the above-described apparatus, comprising the following steps: S1: Place low-level radioactive hazardous waste in an electric furnace and heat it in an oxygen-free environment to achieve gas-solid separation and reduce the volume of radioactive waste. S2: Organic waste gas enters the microwave plasma waste gas treatment device and is decomposed into simple gases at high temperature; S3: The pyrolysis gas enters the deacidification unit to remove acidic components; S4: The deacidified gas enters the cooling device and is reduced to the allowable emission temperature; S5: The cooled gas enters the adsorption device, filters out particulate matter, and is then tested to ensure it meets emission standards.

[0013] The beneficial effects of this invention are as follows: This invention achieves gas-solid separation through oxygen-free heating in an electric furnace, solidifying radionuclides and heavy metals into solid slag. This significantly reduces the volume of radioactive materials disposed of, minimizing landfill space occupation and disposal costs. Furthermore, the high temperature and high oxidizing properties of the microwave plasma torch completely decompose organic pollutants into harmless, simple gases, eliminating long-term environmental risks. In addition, a three-stage tail gas purification process—including a deacidification unit, a cooling unit, and an adsorption unit—effectively removes acidic gases and particulate matter, ensuring compliant emissions and preventing secondary pollution. Simultaneously, the solid slag is collected in a sealed manner, preventing radioactive leakage throughout the process and effectively controlling the risk of nuclide migration. The microwave plasma device offers flexible working gas selection, and the cooling liquid in the cooling unit is recycled, reducing energy consumption and operating costs. The modular, sealed design of each device ensures stable operation and convenient maintenance. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a front view schematic diagram of a microwave plasma treatment device for low-radioactive hazardous waste according to an embodiment of the present invention; Figure 2 This is a top view schematic diagram of a microwave plasma treatment device for low-radioactive hazardous waste according to an embodiment of the present invention.

[0016] In the picture: 1. Electric furnace; 2. Microwave plasma waste gas treatment device; 3. Deacidification device; 4. Cooling device; 5. Adsorption device. Detailed Implementation

[0017] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0018] According to an embodiment of the present invention, a microwave plasma treatment device for low-radioactive hazardous waste is provided.

[0019] Please refer to the instruction manual appendix. Figure 1-2 According to an embodiment of the present invention, a microwave plasma treatment device for low-radioactive hazardous waste includes an electric furnace 1, a microwave plasma waste gas treatment device 2, a deacidification device 3, a cooling device 4, and an adsorption device 5 connected sequentially by pipelines. The electric furnace 1 is configured to achieve an oxygen-free environment by evacuating the furnace or introducing inert gas to replace the air inside the furnace, and to perform oxygen-free heating on the low-radioactive hazardous waste, causing the organic pollutants and volatile inorganic substances in it to vaporize and separate from radioactive nuclides and heavy metals, forming waste gas containing organic matter and solid slag. The electric furnace 1 is also equipped with a slag collection bin for collecting the solid slag containing radioactive nuclides and heavy metals for subsequent safe disposal. The microwave plasma waste gas treatment device 2 has a built-in microwave plasma torch generator, which uses the interaction between high-frequency microwaves and working gas to induce ionization and collision cascade effects, forming plasma gas and generating electrodeless microwave discharge, generating free-floating plasma particles. Utilizing the high-temperature characteristics of these particles, the organic components in the received organic waste gas are decomposed into H2O, CO2, and NO. x The working gas of the microwave plasma torch generator is one or more of the following: inert gas, ordinary air, and waste gas to be treated. The center temperature of the plasma particles can reach up to 3000K, and electrodeless microwave discharge can be initiated in the outflow opening area within about 1 microsecond after the magnetron is turned on. The deacidification device 3, cooling device 4, and adsorption device 5 are configured sequentially to deacidify, cool, and deeply purify the pyrolysis tail gas to achieve compliant gas emissions. Gas-solid separation is achieved through oxygen-free heating in the electric furnace 1, which solidifies radioactive nuclides, heavy metals, etc., into solid slag, significantly reducing the volume of radioactive disposal materials and reducing landfill space occupation and disposal costs. In addition, the high temperature and high oxidizing properties of the microwave plasma torch can completely pyrolyze organic pollutants into harmless simple gases, eliminating long-term environmental risks. Furthermore, the three-stage tail gas purification by the deacidification device 3, cooling device 4, and adsorption device 5 can effectively remove acidic gases and particulate matter, ensuring compliant gas emissions and avoiding secondary pollution. Meanwhile, the solid slag is collected in a sealed manner, with no radioactive leakage throughout the process, effectively controlling the risk of nuclide migration; and the cooling liquid of the cooling device 4 is recycled, reducing energy consumption and operating costs. The modular and sealed design of each device ensures stable operation and convenient maintenance.

[0020] The furnace shell of the electric furnace 1 is made of high-temperature and corrosion-resistant material. The temperature of the oxygen-free heating is controlled within a range that allows the target components in the hazardous waste to be effectively gasified while the solid slag is stably retained. This ensures that the target pollutants can be effectively gasified while the residual slag maintains a stable mineral structure, preventing the re-evaporation of radioactive nuclides.

[0021] In one embodiment, please refer to the appendix to the specification. Figure 1 and Figure 2 As a further embodiment of the present invention, the deacidification device 3 is a ceramic deacidification filter, the core component of which is a porous ceramic filter element with a microporous structure. The porosity of the ceramic filter element is greater than 80%, the micropore diameter ranges from 1 to 10 micrometers, and its surface is coated with an adsorbent or catalyst. In use, when gas passes through the filter element, particulate matter is trapped by the micropores, while acidic gas molecules come into full contact with the adsorbent or catalyst coated on the filter element surface, resulting in rapid chemical adsorption or catalytic conversion, thereby achieving efficient and simultaneous deacidification and dust removal.

[0022] In one embodiment, please refer to the appendix to the specification. Figure 1 and Figure 2 As a further embodiment of the present invention, the cooling device 4 is a spray tower, which has an atomizing spray layer and a packing layer arranged from top to bottom inside. The atomizing spray layer is used to spray coolant onto the rising airflow, and the packing layer is used to increase the gas-liquid contact area. Through evaporative cooling and sensible heat exchange, the high-temperature gas is rapidly cooled and some particulate matter is washed away. In use, the high-temperature gas enters from the bottom of the tower and flows upward. First, it passes through the packing layer and undergoes sufficient sensible heat exchange with the coolant sprayed from the top of the tower, which forms a liquid film on the surface of the packing. Subsequently, the gas rises to the atomizing spray zone and comes into direct contact with the atomized droplets. The droplets absorb the heat of the gas and partially evaporate, carrying away a large amount of latent heat through the evaporative cooling effect, thereby achieving rapid cooling of the gas. At the same time, residual soluble gases (such as residual acidic gases) and some fine particulate matter in the gas can be captured and washed away by the droplets.

[0023] In one embodiment, please refer to the appendix to the specification. Figure 1 and Figure 2 As a further embodiment of the present invention, the adsorption device 5 employs a ceramic dust filter. This ceramic dust filter, through a curved porous ceramic channel, captures particles by interception, inertia, and diffusion effects, achieving a filtration efficiency of no less than 99.9% for particles with a diameter of 0.1 μm. The curved porous ceramic channel effectively captures particulate matter, ensuring the cleanliness of the outlet gas.

[0024] Workflow: First, the low-level radioactive hazardous waste to be treated is fed into an electric furnace 1 for anaerobic pyrolysis, achieving gasification and separation of organic and volatile components, while radioactive nuclides and heavy metals are stabilized and solidified in solid slag. The generated organic waste gas is introduced into a microwave plasma waste gas treatment device 2, where it is instantly and completely decomposed into small molecule harmless gases in an extremely high-temperature plasma environment. Subsequently, the decomposed gas flows sequentially through a deacidification device 3, a cooling device 4, and an adsorption device 5, respectively completing the removal of acidic gases, a rapid drop in gas temperature, and deep filtration of residual fine particulate matter, ultimately obtaining clean and compliant tail gas, which is then discharged after passing testing.

[0025] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A microwave plasma treatment device for low-radioactivity hazardous waste, characterized in that, It includes an electric furnace (1), a microwave plasma waste gas treatment device (2), a deacidification device (3), a cooling device (4), and an adsorption device (5) connected in sequence through pipelines. The electric furnace (1) is configured to achieve an oxygen-free environment by evacuating the furnace or introducing inert gas to replace the air inside the furnace, and to heat the low-radioactive hazardous waste in an oxygen-free environment, so that the organic pollutants and volatile inorganic substances in it are vaporized and separated from radioactive nuclides and heavy metals, forming organic waste gas and solid slag; the electric furnace (1) is also equipped with a slag collection bin for collecting solid slag containing radioactive nuclides and heavy metals, which facilitates subsequent safe disposal. The microwave plasma exhaust gas treatment device (2) has a built-in microwave plasma torch generator. Through the interaction of high-frequency microwaves and working gas, it induces ionization and collision cascade effects, forming plasma gas and generating electrodeless microwave discharge, producing free-floating plasma particles. Utilizing its high-temperature characteristics, it decomposes the organic components in the received organic waste gas into H2O, CO2, and NO. x Simple gases; The deacidification device (3), cooling device (4) and adsorption device (5) are configured in sequence to deacidify, cool and deeply purify the tail gas after pyrolysis, so as to achieve gas emission in compliance with standards.

2. The microwave plasma treatment device for low-radioactivity hazardous waste according to claim 1, characterized in that, The furnace shell of the electric furnace (1) is made of high temperature and corrosion resistant material, and the temperature of the oxygen-free heating is controlled within a range that enables the target components in the hazardous waste to be effectively gasified and the solid slag to be stably retained.

3. The microwave plasma treatment device for low-radioactivity hazardous waste according to claim 1, characterized in that, The working gas of the microwave plasma torch generator is one or more of inert gas, ordinary air, and waste gas to be treated; the center temperature of the plasma particles can reach up to 3000K, and electrodeless microwave discharge can be started in the outflow opening area within about 1 microsecond after the magnetron is turned on.

4. The microwave plasma treatment device for low-radioactivity hazardous waste according to claim 1, characterized in that, The deacidification device (3) is a ceramic deacidification filter, the core component of which is a porous ceramic filter element with a microporous structure. The porosity of the ceramic filter element is greater than 80%, the micropore diameter range is 1-10 micrometers, and its surface is coated with an adsorbent or catalyst.

5. The microwave plasma treatment device for low-radioactivity hazardous waste according to claim 1, characterized in that, The cooling device (4) is a spray tower, which has an atomized spray layer and a packing layer arranged from top to bottom inside. The atomized spray layer is used to spray coolant onto the rising airflow, and the packing layer is used to increase the gas-liquid contact area. Through evaporative cooling and sensible heat exchange, the high-temperature gas is rapidly cooled and some particulate matter is washed away.

6. The microwave plasma treatment device for low-radioactivity hazardous waste according to claim 1, characterized in that, The adsorption device (5) uses a ceramic dust filter. The ceramic dust filter captures particles through a curved porous ceramic channel by means of interception, inertial action and diffusion effect. The filtration efficiency for particles with a diameter of 0.1 μm is not less than 99.9%.

7. A microwave plasma treatment device for low-radioactivity hazardous waste according to any one of claims 1-6, characterized in that, The processing flow is as follows: S1: Place the low-level radioactive hazardous waste in an electric furnace (1) and heat it in an oxygen-free environment to achieve gas-solid separation and volume reduction of radioactive waste. S2: Organic waste gas enters the microwave plasma waste gas treatment device (2) and is decomposed into simple gas at high temperature; S3: The pyrolysis gas enters the deacidification unit (3) to remove acidic components; S4: The deacidified gas enters the cooling device (4) and is cooled to the allowable emission temperature; S5: The cooled gas enters the adsorption device (5), and after filtering particulate matter, it is tested and discharged in compliance with standards.

Images